초록 ▼

A feedforward throttle adjustment for a closed loop idle speed control provides engine power output required to drive a variable power steering load while maintaining the engine idle speed in a desired range. The working pressure of the power steering system is detected, and the change in such press

A feedforward throttle adjustment for a closed loop idle speed control provides engine power output required to drive a variable power steering load while maintaining the engine idle speed in a desired range. The working pressure of the power steering system is detected, and the change in such pressure in the course of a steering maneuver is used to initiate an increase in the engine power output setting. The increase is determined in relation to the peak pressure change; it is implemented at a pedetermined rate, and is subject to interruption whenever the pressure change indicates that the steering maneuver has ended.

대표청구항 ▼

In a motor vehicle including an engine for supplying the input power requirement of a power assist steering system which develops a working pressure in relation to the level of steering assist demanded by the operator of the vehicle, where the engine power output under idle conditions is governed by

In a motor vehicle including an engine for supplying the input power requirement of a power assist steering system which develops a working pressure in relation to the level of steering assist demanded by the operator of the vehicle, where the engine power output under idle conditions is governed by the setting of an adjustable engine power control mechanism, an engine idle speed control system comprising: closed loop idle speed control means for effecting relatively slow adjustment of the engine power control mechanism in relation to the difference between the actual engine idle speed and a desired engine idle speed value so as to bring the actual idle speed into substantial correspondence with the desired idle speed, the adjustment rate being chosen to provide control stability under steady state engine idle conditions; and feedforward idle speed control means for effecting relatively fast adjustment of the engine power control mechanism in response to changes in the input power requirement of the power assist steering system, the feedforward idle speed control means being effective: (A) when the working pressure of the steering system is increasing (1) to detect the amount of pressure increase as an indication of the increase in the input power requirement of the steering system, (2) to determine a maximum adjustment value for said engine power control mechanism in relation to the detected pressure increase, (3) to effect open loop adjustment of the engine power control mechanism for increasing its setting by said maximum adjustment value, the rate of such open loop adjustment being limited by a maximum adjustment rate which avoids engine stalling while minimizing overshoot of the desired engine idle speed; and (B) when the working pressure of the steering system is decreasing to (1) detect the amount of pressure decrease as an indication of the decrease in the input power requirement of the steering system, and (2) interrupt the open loop adjustment of the engine power control mechanism as soon as the detected pressure decrease exceeds a reference pressure change indicative of a substantial reduction in the input power requirement of the steering system, thereby to avoid unnecessary overshoot of the desired engine idle speed upon completion of a steering maneuver.